- MFT: Fixed segmentation fault when reading rows

# Problem surfaces when using FreeTDS, ASE 12.5 and reading text fields
# with NULL values. This is essentially a workaround for a bug in Free-
# TDS which is not setting the NULL indicators correctly, but provides
# a protection against possible segfaults if any other driver ever does
# this again:-)

1 files changed, 11 insertions, 2 deletions

diff --git a/ext/sybase_ct/php_sybase_ct.c b/ext/sybase_ct/php_sybase_ct.c
index afc2537914..3b11af25f9 100644
--- a/ext/sybase_ct/php_sybase_ct.c
+++ b/ext/sybase_ct/php_sybase_ct.c
@@ -1248,8 +1248,17 @@ static int php_sybase_fetch_result_row (sybase_result *result, int numrows)
 					}
 					
 					default: {
-						/* This indicates anything else, return it as string */
-						ZVAL_STRINGL(&result->data[i][j], result->tmp_buffer[j], result->lengths[j]- 1, 1);
+						/* This indicates anything else, return it as string
+						 * FreeTDS doesn't correctly set result->indicators[j] correctly
+						 * for NULL fields in some version in conjunction with ASE 12.5
+						 * but instead sets result->lengths[j] to 0, which would lead to
+						 * a negative memory allocation (and thus a segfault).
+						 */
+						if (result->lengths[j] < 1) {
+							ZVAL_NULL(&result->data[i][j]);
+						} else {
+							ZVAL_STRINGL(&result->data[i][j], result->tmp_buffer[j], result->lengths[j]- 1, 1);
+						}
 						break;
 					}
 				}